1. Field of the Invention
The present invention relates to a video and audio reproducing apparatus that reproduces and outputs video data and audio data recorded on a recording medium, such as an optical disk or the like, at a fast speed in a forward direction or a backward direction, and a method thereof.
2. Description of the Related Art
Generally, a recording medium in which video or audio, and sub-video are encoded according to a DVD-Video standard and then compressed and recorded, and a reproducing apparatus thereof have been put into practical use. In this reproducing apparatus, not only common reproducing but also special reproducing, such as forward reproducing at a fast speed or backward reproducing at a fast speed, can be performed. According the DVD-Video standard, in a VOBU (Video Object Unit) that is a logical minimal reproducing unit, navigation data (NV_PCK) for controlling reproducing of the VOBU as shown in FIG. 2 is recorded, in addition to presentation data like video data (V_PCK) or audio data (A_PCK) or sub-picture data (SP_PCK).
As shown in FIG. 3, PCI_GI (general information of PCI), NSML_AGLI (non-seamless angle information), HLI (highlight information), and RECI (recording information) are included in the navigation data (NV_PCK). Further, as shown in FIG. 5, DSI_GI (general information of DSI), SML_PBI (seamless playback information), SML_AGLI (seamless angle information), VOBU_SRI (VOBU search information), and SYNCI (synchronization information) are included in the navigation data (NV_PCK). As shown in FIG. 6, in the VOBU-SRI, start addresses of the VOBU that are reproduced before and after 0.5×N seconds (N indicates integers of from 1 to 15) including right before or right after reproducing the VOBU, 10 seconds, 30 seconds, 60 seconds, and 120 seconds, are described.
The forward reproducing at a fast speed and the backward reproducing at a fast speed can be achieved by intermittently reproducing the VOBU by the VOBU_SRI, and the fast reproducing speed can be adjusted by varying the referencing location in the VOBU_SRI. That is, if the reproducing time of the VOBU is 0.5 second, the interval of the VOBU_SRI is also a unit of the 0.5 second. When forward reproducing at double speed is performed, an address of the VOBU reproduced after 1 second if N=2 is acquired from the VOBU_SRI to reproduce it, and when forward reproducing at quadruple speed is performed, an address of the VOBU reproduced after 2 seconds if N=4 is acquired from the VOBU_SRI to reproduce it (for example, see JP-A-10-126743)
However, since the reproducing time of the VOBU determined according to the DVD-Video standard is within a range of 0.4 to 1.2 seconds, it is not constant. Since the time interval at which the description is made in the VOBU_SRI is 0.5 second, if the referencing location in the VOBU_SRI is fixed at a fast speed, the accurate speed cannot be obtained. For example, in a case in which 2× reproducing is performed, even when an address of the VOBU reproduced after one second as N=2 is acquired and reproducing is performed, if the reproducing time of the VOBU is one second, it may become actually common reproducing. Similar to it, in a case in which 4× reproducing is performed, even when an address of the VOBU reproduced after 2 second as N=4 is acquired and reproducing is performed, if the reproducing time of the VOBU is one second, it may become actually the reproducing at 2×.